Many vehicles are used over a wide range of vehicle speeds, including both forward and reverse movement. Some types of engines, however, are capable of operating efficiently only within a narrow range of speeds. Consequently, transmissions capable of efficiently transmitting power at a variety of speed ratios are frequently employed. When the vehicle is operating at a low speed, the transmission is usually operated at a high speed ratio such that it multiples the engine torque for improved acceleration. At high vehicle speed, operating the transmission at a low speed ratio permits an engine speed associated with quiet, fuel-efficient cruising.
These transmissions can also incorporate a park-by-wire system. In a park-by-wire system, a controller commands movement of a parking mechanism, engaging a parking pawl with an associated toothed gear of a wheel. Mechanical components, such as springs, can be implemented to bias the parking mechanism into either an engaged or disengaged state absent any commanded force on pawl from the controller. Assembly of springs can be cumbersome and awkward during the manufacturing process, especially if the spring is surrounded by other components with tight spacing.